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Sept. 11, 1928.

R. W. DAVENPORT HEAT ENGINE Original Fil ed Nov. 29, 1922 w INVENTOReissued Sept. 11, 1928.

msou w. DAVENPORT, or nrirnorr, r001. comm, or NEW xoax,

moment, it. 1., acoaroaunon or. new JERSEY.

assmnon 'ro cnrcaoo IPNEUHATIO nan.- Enema,

Original application iiled November 28, 1824, Serial No. 708,936.Original December 31, 1927. Serial No. 244,032.

My invention consists in improvements in heat engines and isparticularly adapted to employ in certain thermodynamic operationsthenovel working substance described and copending application filedSerial No. 603,998, (Pat- March 1st, 1927) of claimed in my November 29,1922, ent No. 1,619,194 issued which original application the presentapplication is a division; and for performing u on the said novelworking fluid such heat transforming operations as are described anclaimed in my application filed .Serial N o. 570,015 alsocopending.

This present and the two aforesaid inventions constitute a closelyrelated series of inventions.

Besides the abovementioned objects, the

resent invention provides means for utilizing the peculiar advantagesinherent in the aforesaid inventions, and applying them to the practicalcooling of refrigerators. An other object is to provide a refrigeratingcabinet so arrange and constructed as to afford maximum food storagespace with minimum exposure to external heat. Other objects of myinvention will appear hereinafter.

All refrigerating apparatus of the com pression type hitherto known orused falls into one of two perfectly distinct and separate classes, i.e., the vapor-compression class or compressor-condenser-expandertype,and the cold air type or compressor-cooler-expansion motor class. Thisseparation is but the natural result of the essential and basicdifferences between ants used in the former, and the ideal gas byvaporization of refrigerants used in the latter class of apparatus. Itisemphasized that in the vapor compression type of heat en 'ne therefrigerating effect is obtained not y expansion but liquid at constanttemperpressure, which liquid is fed as through a loosely called theexpansion valve, whereas in t e cold air machine the entirerefrigerating efiect is obtained by expending air or other gas (notvapor) in an ex ansion motor.

y improved heat engine differs from both the above described types ofheat engine in June 21, 1922,-

the liquid-vapor refrigerworking substance of the .tioned, with-a supplyof refrigerator, and'the vapor larch 1, 1927. I Application for reissuemed thatl employ' both an expansion device and a boiler or vaporizingelement in novel com- 1922, Serial No. 603,988. Divided and applicationfiled April 25, No. 1,619,195, date'd bination with acompressor and acondenser,

and in other respects hereinafter set forth, and is depicted in certainrepresentative forms in t e. accompanying drawings.

Fig. 1 is afront elevation-section of a form of my invention includingthe refrigerator.

Fig. 2 is a side view of parts of same. In the form shown in whichfigures like parts have like numerals, my invention may be described asfollows:

1 is an' electric motor geared to a compressor 2 which discharges intocondenser 3. The

.evaporator is in general thin and flat and as shown comprises theheaders 4 and 5 connected by the ribbon-shaped duct 6, with theseparator 7 forming the outlet and nozzle 8 the inlet. The hollowribbon-shaped portion of the evaporator is made of sheet material,

preferably metal, and provides opposed surfaces in close-proximit so asto present a maximum external sur ace area for a minimum quantity ofevaporatin li outlet 7 is connected tb the inta e o the pump 2 by the pie 9, and the inlet nozzle 8 is connected to't e condenser 3 by the pipe10 Figs. 1 and 2,

which is placed inside the pipe 9 to form a heat exchanger therewith.

The insulated refrigerator cabinet -11 con= tains compartments 12 and 13each of which may also be insulated, and the evaporator traverses allthree as shown. Shelves 14 to 17 may be used to carry the articles to becooled.

This embodiment of. my invention operates substantially as follows:After charging the system with aproper quantity of suitable type beforementhe liquid component in the evaporator as shown, and air and vapor inthe rest of the-space, the motor 1 is started and the compressor 2compels the the wor circulation of mg substance. The total pressureinthe evaporator 4-5-6 falls while the total pressure in the condenser3- rises, thus causing the liquid in the evaporator to evaporate andabsorb heat from the in the condenser eject h'eatto-any suitable cooltoliq'uefy and ing med um as airor water (not shown). :m.

The expander 8 offers suitable resistance to the flow of gas vapor andliquid fed to it in contiguous streams through duct 10 from thecondenser, thus maintaining suitable difference in pressure betweencondenserand evaporator. The liquid in the evaporator is caused toemulsify with the gas and vapor by the action of the expander 8, andthis I find to be of great advantage in facilitating evaporation andrapid cooling of liquids of relatively low va or tension, such asalcohol etc, which,.in t e old vapor compression types of heat engine,lacking my combination of expander and evaporator, lie inert and unableto produce ractical refrigerating effect. It is to be understood thatthe indicated gauge suction or back pressure is higher than thatcorresponding with the temperatureof the liquid refrigerant, whichtemperature is limited only by effective at a given time and place.

By the combination with theexpander, of my improved emulseur-evaporator,I am enabled to derive the further advantage of operating at a pluralityof refrigerating temperatures, since I find that the lower header 4tends to be colder thanthe upper header 5, when circulation between themis restricted by any suitable means, such as the flattened orribbon-shap ed-duct 6. I may apply this peculiar advantage in anydesired way as for example, by com ining my improved evaporator withsuitably insulated chambers 12 and 13'so disposed that the lower one 12is colder than the others, while chamber 13 is a little higher up andnearer'header 5 will be warmer and the main chamber or cabinet itselfmay be still milder in temperature. By this arrangement water may befrozen in ice-chamber 12, raw meats, milk, butter etc. may be kept attemperatures around that of melting. ice in chamber 13, while the maincompartments formed by the shelves 15, 16, 17 maybe kept at, forinstance, degrees F. for general articles such as cooked foods and rawvegetables.- Since the bulk of the heat transfer occurs at thisrelatively high temperature, I am enabled to procure much higher economythan was possible where the refrigerant must be evaporated at atemperature and pressure low enough to makeice, while the cabinet itselfwas operated at a lower temperature than is really needed, as wasnecessarily the case with all former refrigerators, cooled by mechanicalmeans.

The evaporator 4, 6, 5 extends from to to od bottom and from front toback of the till storage space and presents a heat absorbing surface ofsubstant al extent by reason of the thin-and flat portion 6 thereof. Thepeculiar form of the evaporator and its disposition vertically andcentrally of the refrigerator results in a minimumand, in effect, analmost imperceptible loss of food storage space. With such an'elementthe loss of storage space the partial vapor pressure of my improvedrefrigerant with the said series a stream of mixed is easily kept downto one-tenth or less. Hence the application of this feature of theinvention. to any refrigeratin cabinet will provide a'maximum of availabe food storage space. For a food compartment of any given size a cabinetwith a minimum exterior heat can be provided by mounting in thecompartment an evaporating element in the form of a relatively thin andflat member presenting a large area for heat absorption ut occupying anegligible amount of space. Besides the obvious advantages of myinvention, other advantages inhe-re such as the fact that with the aidof my improved refrigerant before mentioned, my apparatus may be madeself-regulating. For example, using carbon tetrachlorideas the liquidcomponent of my working substance, the freezing point of which is aroundzero F., the nozzle 8 freezes up at this temperature thus limiting thetemperature in all compartments of the"refrig erator and simultaneouslyunloading the coin pressor so that the power required is practically aslow as that with blanked intake. The costly and troublesome thermostatalways a vital part ofthe former automatic refrigerating machines is. byvirtue of the cooperation invention, done away with.

L kewlse the trouble-making expansion valve which, in the old systems,was always required in order to maintain the liquid seal essentialbetween the condenser and expander, is, by my invention, dispensed withalong with the seal.

The reversibility of the heat engine above described may beextraordinarily high owing tor.

I claim present to the temperature gradient in the refrigera-- exposureto 1. Refrigerating apparatus utilizing as a refrigerant a physicalmixture of a liquid and rable liquid disposed in thermal relation withsaid chambers, ducts arranged to eonnect said vessels to form a nozzlefor expending into the first vessel of gas and vapor, means for removinggas and va or from the lastvessel of the series to provi e the streamseries, means including aforced into said first vessel, and means insaid cycle for maintaining the aforesaid liquid in sa d vessels ponentscomprising 3. In a heat engine of the compressor-condenser-evaporatortype utilizing as a working substance a liquid and a gas substantiallyinert and insoluble in the liquid, a compressor, a condenser, and anevaporator, said evaporator for containing a body ofsaid liquid, a DeLaval nozzle arranged to'discharge into said evaporator, and a singlepipe connecting said nozz'le with said condenser, said nozzle areabeinso proportioned as to pass contiguously 0th the liquid and the gaseouscomponents of the refrigerant.

4. In refrigerating apparatus for utilizing a refrigerant having liquidand gaseous components, an evaporator arranged to contain a ody of theliquid component of the refrigerant, means continuously to force thegaseous component of the refrigerant in a closed cycle into and throughsaid body in said evaporator, and means for withdrawing heat from saidgaseous comp nent at one point in said cycle.

5. Refrigerating apparatus for utilizing arefrigerant having'liquid andgaseous coman evaporator arranged to contain a body of the liquidcomponent of the refrigerant, means Gontinuously to withdraw the gaseouscomponent and the vapor of the refrigerant from the-evaporator, coolsaid mixture and liquefy the refrigerant and return said mixed liquidand gas to the bottom ment for containing ponents comprising a of theevaporator.

6. Refrigerating-apparatus for utilizing a refrigerant having liquid andaseous components comprising a heat absor ing elementfor containing theliquidcomponent of the refrigerant, a pump withdrawing the gaseouscomponent of the refrigerant from the top of said element, a heatejecting device through which said gaseous component is forced by saidpump, and a duct leading from said device to the base of said elementand providing a restricted opening so proportioned as to pass themingledcondensed and non-condensable components of the circulated refrigerantwhich expand directly into and up through the liquid in said element.

7. Refrigerating apparatus for utilizing a refrigerant having liquid andgaseous components comprising a heat absorbing elethe liquid componentof the refrigerant, a pump withdrawing the gaseouscomponent of therefrigerant from the top of said element, a heat ejecting device throughwhich saidgaseous component 1s forced by said pump, and a duct leadingfrom said device .to the base of said element and terminating in a DeLaval nozzle, the nozzle .area being so proportioned asto passcontinuously and in contiguity both the condensed andnon-condensable'products of said heat ejecting-device.

8. Refrigerating apparatus for utilizing a refrigerant having llqllldand gaseous comheat absorbing element said element, a heat ejectingdevice through ponents comprising a meat absorbing element forcontaining the liquid component of the refrigerant, a pump withdrawingthe gaseous component of the refrigerant from the top of said element, aheat'ejecting device through which said gaseous component is forcedbysaid pump, and a duct leading from said device to the base of saidelement and providing a restricted opening of such size as to pass themingled condensed and non-condensable components of the circulatedrefrigerant directly into the liquid in said element, said duct beingbrought into thermal contact with the relatively colder gaseouscomponent being withdrawn from the top of said element by said pumpthereby to precool the circulated refrigerant.

10. Refrigerating apparatus for utilizing a refrigerant having liquidand gaseous components comprising a heat absorbing element forcontaining the liquid component of the refrigerant, a pump withdrawingthegaseous component of the refrigerant from the top of said element, aheat ejecting device through which said gaseous component is forced bysaid pump, and a duct leading from said device to the base of saidelement and providing a restricted opening of such size as to pass themingled condensed and non-condensable components of the circulatedrefrigerant directly into the liquid in said element,

a portion of said duct being disposed within the top of said elementthereby to precool the circulated refrigerant.

11. In refrigerating apparatus for utilizing as a refrigerant a physicalmixture of a liquid and a gas substantially inert to and insoluble insaid liquid, a refrigerating element arranged to contain a body of theliquid portion of the refrigerant, and means producing a rapidebullition of said liquid comprising members forming a closed cyclethrough which the gaseous portion of the refrigerant is circulated andincluding a continuously open port in said element through which saidgaseous component is forced to bubble up' through said liquid component.

12. In refrigerating-apparatus for utilizing as a refrigerant a physicalmixture of 'a liquid and a gas substantially inert to and inarranged tocontain a bod soluble in said liquid, a refrigerating element of theliquid means producing a rapid e ullition of sai liquid body including acompressor arranged to withdraw the gas and t e vapor of the liquid fromsaid element and return the same under pressure to said element adjacentthe bottom thereof, and means for removing heat from said gas-vaporstream before it is re turned to said element.

13. In refrigerating apparatus for utilizing as a refrigerant, aphysical mixture of a liquid and a gas substantially inert to andinsoluble in said liquid, a refrigerating element. arranged to contain abod of the liquid, a compressor arranged to witl idraw' the gas and thevapor of the'li aid from said element, means for removing eat from saidgas-vapor stream, and means for returning said gasvapor stream underpressure to said element comprising a continuously open port in saidelement. r

r 14. In refrigerating; apparatus for utilizing asa refrigerant, aphysical mixture of a liquid and a gas substantially inert to andinsoluble in said liquid, a refrigerating element for containing a bodyof the liquid, a compressor arranged to withdraw the'gas and the vaporof the liquid from said element, means for condensing at least a part ofsaid vapor, means for precooling said gas-vaporliquid stream, and meansfor returning said gas-vapor-liquid stream under pressure to saidelement comprising a continuously open port in said element.

15. A refrigerator having insulated walls and an elongate refrigeratingelement vertically disposed therein, and means causing said element toabsorb heat from said refrig ,crato-r at different temperatures atvertically spaced points thereof.

16. Refrigerating apparatus including a cabinet having insulated walls,an elongated thin flat refrigerating element. vertically disposedtherein for containing liquid, and means for causing said liquid toevaporate at different temperatures at vertically spaced points thereof.

17. A refrigerator having insulated walls and an elongate refrigeratingelement vertically disposed therein, and means causing.

said element to absorb heat from said refrigcrator at upwardly spacedpoints on said element at progressively higher temperatures.

18. A refrigerator having at least three separate heat insulatedcompartments and a single heat absorbing element in thermal contact withthe interior of all said compartments. said compartments and saidelement being so arranged that heat is removed from said compartment atdifferent temperatures.

19. A refrigerator having heat insulated walls and a heat absorbingelement therein vertically disposed and extending substantiall from thebott m to the top of the spacewas "an i to be cooled and a series of searately insulated compartments within sai space artly enclosing saidelement and maintained 8 latter at progressively higher temperature.

20. A refrigerator having heat insulated walls providing an interiorspace to be cooled, a compartment in the bottom of said space maintainedat a tem rature below freezing, a compartment a ve said' first namedcompartment to be maintained at a temperature slightly above freezing,the remainder of the space being arranged to be maintained at asomewhat-higher tempera ture and a single heat absorbing unit havingparts in thermal contactwith the interior of each of said compartments.

21. A cabinet having a food storage compa rtment and means forextracting heat from said compartment comprising a thin elongateevaporator element disposed in said compartment and in contact with theatmosphere thereof, said element being formed of sheet materialproviding opposed surfaces in close proximity.

22. A cabinet having a food storage com- 'partment and means forextracting heat from said compartment comprising a thin elongateevaporator element formed of sheet material providing opposed surfacesin close prox-' mity, the element being so disposed as to take upone-tenth or less of the space within the compartment.

' 23., A cabinet having a food storage compartment and means forextracting heat from said compartment comprising a hollow ribbon likeevaporator element vertically disposed. in sai compartment and occupyingnot more than one-tenthof the space therein.

24. A refrigerator cabinet having a food storage compartment and meansfor extractingheat from said compartment comprising a hollow, flat andribbon like container'for a volatile liquid, said container beingvertically disposed in said compartment andv occupying one-tenth or less'of the space within said compartment.

25. A refrigerator'eabinet having a storage compartment inclosed by heatinsulating walls, a hollow, flat and ribbon like evaporator elementvertically disposed in said compartment for extracting heat therefrom,and means utilizing the heat absorbing properties of the lower portionof said evaporator for the. freezing of liquids.

26. A cabinet having a food storage compartment and means for extractingheat from said compartment comprising an element for containing anevaporable liquid, said element presenting opposed surfaces in closeproximity and an extended surface area approximating the maximum inrelation to its cubical content and disposed in said compartmglnt so asto cause as little lost space as pos- S] e 27} A abinet hav ng a fo d str g compartmen t and means for extracting heat from said compartmentcomprising an element for containing an evaporable liquid, said elementbeing thin, flat and ribbon like to pre- 5 sent an extended surface areaapproximating the max tent, sari imum in relation to its cubical condelement being disposed vertically and substantially centrally of saidcompartment.

Signed by me at of N. Y., and State of N. Y. this 10th day December,1927.

RAN-$0M W. DAVENPORT.

New York, in the county

